LeetCode in Kotlin

1859. Sorting the Sentence

Easy

A sentence is a list of words that are separated by a single space with no leading or trailing spaces. Each word consists of lowercase and uppercase English letters.

A sentence can be shuffled by appending the 1-indexed word position to each word then rearranging the words in the sentence.

• For example, the sentence "This is a sentence" can be shuffled as "sentence4 a3 is2 This1" or "is2 sentence4 This1 a3".

Given a shuffled sentence s containing no more than 9 words, reconstruct and return the original sentence.

Example 1:

Input: s = “is2 sentence4 This1 a3”

Output: “This is a sentence”

Explanation: Sort the words in s to their original positions “This1 is2 a3 sentence4”, then remove the numbers.

Example 2:

Input: s = “Myself2 Me1 I4 and3”

Output: “Me Myself and I”

Explanation: Sort the words in s to their original positions “Me1 Myself2 and3 I4”, then remove the numbers.

Constraints:

• 2 <= s.length <= 200
• s consists of lowercase and uppercase English letters, spaces, and digits from 1 to 9.
• The number of words in s is between 1 and 9.
• The words in s are separated by a single space.
• s contains no leading or trailing spaces.

Solution

import java.util.TreeMap

class Solution {
    fun sortSentence(s: String): String {
        val words = s.split(" ".toRegex()).dropLastWhile { it.isEmpty() }.toTypedArray()
        val treeMap = TreeMap<Int, String>()
        for (word in words) {
            val key = (word[word.length - 1].toString() + "").toInt()
            treeMap[key] = word.substring(0, word.length - 1)
        }
        val sb = StringBuilder()
        for ((_, value) in treeMap) {
            sb.append(value)
            sb.append(" ")
        }
        return sb.substring(0, sb.length - 1)
    }
}

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